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e92a88272e
spotted by Qingqing Zhou. The HASH_ENTER action now automatically fails with elog(ERROR) on out-of-memory --- which incidentally lets us eliminate duplicate error checks in quite a bunch of places. If you really need the old return-NULL-on-out-of-memory behavior, you can ask for HASH_ENTER_NULL. But there is now an Assert in that path checking that you aren't hoping to get that behavior in a palloc-based hash table. Along the way, remove the old HASH_FIND_SAVE/HASH_REMOVE_SAVED actions, which were not being used anywhere anymore, and were surely too ugly and unsafe to want to see revived again. |
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| .. | ||
| ipc.c | ||
| ipci.c | ||
| Makefile | ||
| pmsignal.c | ||
| procarray.c | ||
| README | ||
| shmem.c | ||
| shmqueue.c | ||
| sinval.c | ||
| sinvaladt.c | ||
$PostgreSQL: pgsql/src/backend/storage/ipc/README,v 1.4 2003/11/29 19:51:56 pgsql Exp $ Mon Jul 18 11:09:22 PDT 1988 W.KLAS Cache invalidation synchronization routines: =========================================== The cache synchronization is done using a message queue. Every backend can register a message which then has to be read by all backends. A message read by all backends is removed from the queue automatically. If a message has been lost because the buffer was full, all backends that haven't read this message will be told that they have to reset their cache state. This is done at the time when they try to read the message queue. The message queue is implemented as a shared buffer segment. Actually, the queue is a circle to allow fast inserting, reading (invalidate data) and maintaining the buffer.